A wide variety of beams are incorporated in vehicle structures. Transverse or cross car beams may be provided that extend between longitudinal frame rails or integrally formed rails. Pillars are beams that support the roof of a vehicle to resist crush loads. Bumper support beams extend between a vehicle frame and front or rear bumpers to absorb energy in front end or rear end impacts. There is a general need to reduce the weight of vehicles to improve fuel economy. and exhaust emissions. Concomitantly, vehicle safety standards require strengthening of beams and increasing energy absorption. Stronger lighter-weight materials are being incorporated in vehicle beams primarily by changing the material of the beams. However, merely changing materials is not thought to be sufficient to minimize weight while improving bending resistance and crush load absorption.
Beams having more than four sides have been developed in an effort to reduce weight while improving bending strength and crush resistance. For example, beams having 12 to 20 sides have been proposed that increase the strength of the beam. One problem presented by these types of beams is that joining the beams to other frame parts requires forming irregular shaped brackets and receptacles. Irregular brackets and receptacles are more difficult to form and require costly manufacturing processes.
The present disclosure is directed to achieving fuel economy driven weight reduction in vehicle beams and structural members while maximizing bending strength and crush load energy absorption in vehicles.